more

Makefile

@@ -4,10 +4,10 @@ NONDOC = cpdfyojson cpdfxmlm cpdfutil
 DOC = cpdfunicodedata cpdferror cpdfdebug cpdfjson cpdfstrftime cpdfcoord \
       cpdfattach cpdfpagespec cpdfposition cpdfpresent cpdfmetadata \
       cpdfbookmarks cpdfpage cpdftruetype cpdfremovetext cpdfextracttext \
-      cpdfembed cpdfaddtext cpdfimage cpdffont cpdftype cpdfpad cpdfocg \
+      cpdfembed cpdfaddtext cpdffont cpdftype cpdfpad cpdfocg \
       cpdfsqueeze cpdfdraft cpdfspot cpdfpagelabels cpdfcreate cpdfannot \
       cpdfxobject cpdfimpose cpdftweak cpdftexttopdf cpdftoc cpdfjpeg \
-      cpdfpng cpdfdraw cpdfcommand
+      cpdfpng cpdfimage cpdfdraw cpdfcommand
 
 MODS = $(NONDOC) $(DOC)
 

cpdfimage.ml

@@ -22,6 +22,7 @@ let pnm_to_channel_24 channel w h s =
         done
       done
 
+(* FIXME do this all at once *)
 let write_stream name stream =
   let fh = open_out_bin name in
     for x = 0 to bytes_size stream - 1 do
@@ -29,8 +30,34 @@ let write_stream name stream =
     done;
     close_out fh
 
+(* Detect images we can write directly as PNGs, to avoid going through pnm2png or imagemagick.
+This is when BPC = 8, colourspace = DeviceRGB or CalRGB, compression is /FlateDecode. *)
+let write_image_png pdf resources name dict =
+  (*Printf.printf "%s\n" (Pdfwrite.string_of_pdf (Pdf.direct pdf dict));*)
+  match
+    Pdfimage.colspace pdf dict resources,
+    Pdfimage.bpc pdf dict,
+    Pdf.lookup_direct pdf "/Filter" dict
+  with
+  | (Pdfspace.DeviceRGB | Pdfspace.CalRGB _),
+    Some (Pdf.Integer 8),
+    Some (Pdf.Name "/FlateDecode" | Pdf.Array [Pdf.Name "/FlateDecode"]) ->
+      (*Printf.printf "Direct to png...\n";*)
+      Pdf.getstream (Pdf.direct pdf dict);
+      let ch = open_out_bin (name ^ ".png") in
+      let o = Pdfio.output_of_channel ch in
+      let width = match Pdf.lookup_direct pdf "/Width" dict with Some (Pdf.Integer x) -> x | _ -> raise Exit in
+      let height = match Pdf.lookup_direct pdf "/Height" dict with Some (Pdf.Integer x) -> x | _ -> raise Exit in
+      let idat = match Pdf.direct pdf dict with Pdf.Stream {contents = (_, Got bytes)} -> bytes | _ -> raise Exit in
+        (*Printf.printf "all ok...\n";*)
+        Cpdfpng.write_png {width; height; idat} o;
+        close_out ch;
+        true
+  | _ -> false
+
 let write_image path_to_p2p path_to_im pdf resources name image =
-  match Pdfimage.get_image_24bpp pdf resources image with
+  let main () =
+    begin match Pdfimage.get_image_24bpp pdf resources image with
     | Pdfimage.JPEG (stream, _) -> write_stream (name ^ ".jpg") stream
     | Pdfimage.JPEG2000 (stream, _) -> write_stream (name ^ ".jpx") stream
     | Pdfimage.JBIG2 (stream, _) -> write_stream (name ^ ".jbig2") stream
@@ -66,6 +93,12 @@ let write_image path_to_p2p path_to_im pdf resources name image =
           end
     | _ ->
         Printf.eprintf "Unsupported image type when extracting image %s %!" name
+    end
+  in
+    match write_image_png pdf resources name image with
+    | true -> ()
+    | exception x -> Printf.printf "Failed to write PNG directly (%s)\n" (Printexc.to_string x); main ()
+    | _ -> main ()
 
 let written = ref []